window.onload = function(){
    let time = 10;
    setInterval(()=>{
        time--;
        document.getElementById("num").innerHTML = time;

        if(time == 0){
            location.href ="https://www.baidu.com/";
        }
        
    },1000)
}
//做 立即返回
document.getElementById("btn").onclick = function(){
    location.href = "https://www.baidu.com/";
}